pass1b.c (clone_file_block): Fix bugs when cloning extended attribute

pass1b.c (clone_file_block): Fix bugs when cloning extended attribute
	blocks.  Moved free of block_buf to after the code which clones the
	extattr block, and fixed logic for changing pointers to the extended
	attribute field in the inodes which were affected.

(decrement_badcount): New function which is used whenever we need to
	decrement the number of files which claim a particular bad block.
	Fixed bug where delete_file wasn't checking check_if_fs_block() before
	clearing the entry in block_dup_map.  This could cause a block which
	was claimed by multiple files as well as the filesystem metadata to
	not be completely fixed.